The ozone loss over the Arctic was so severe this year that for the first time a ‘hole’ in the ozone layer, similar to the one over the Antarctic, appeared.

At a level of around 13 miles above the ground, 80 per cent of the ozone was lost, potentially exposing people on Earth’s surface to harmful ultraviolet-B rays from the sun, which can cause sunburn and skin cancer.

The loss happened not because of increased use of ozone-destroying chemicals – now banned, and rarely used – but because cold high-altitude weather made the existing chemicals ‘more active’.

The paper, published in science journal, Nature, said: ‘Chemical ozone destruction over the Arctic in early 2011 was — for the first time on record — comparable to that in the Antarctic ozone hole.’

Data showing ozone destruction was released in April, but this is the first full analysis of the effect in the Arctic. Scientists cannot predict whether the effect will persist – but under certain conditions, predict ‘severe ozone loss’.